Concentrations of mesophilic bacteria in a poultry farm over two fattening periods focusing on the presence of staphylococci and enterococci.

The increasing animal numbers have a potential impact on the air quality of stables. The aim of this study was to assess the microbial load in the barn air from the day of entry of the chickens to the day of removal for slaughter. A total of 10 measurements in two fattening periods were conducted in a poultry farm with a capacity of 400 chickens in Styria, Austria. The samples were collected with an Air-Sampling Impinger for the investigation of mesophilic bacteria, staphylococci and enterococci. Chicken skin swab samples were collected to detect Staphylococcus aureus. The total colony forming units per cubic meter of mesophilic bacteria of the first measurement series of period I was 7.8 × 10⁴ and increased to 1.4 × 10⁸ at the end and at the fattening period II it increased from 2.5 × 10⁵ to 4.2 × 10⁷. In the measurement series of the fattening period I, the concentration of Staphylococcus spp. increased from 0 to 4.9 × 10⁷ CFUs/m³ and from 0 to 2.1 × 10⁷ CFUs/m³ in the fattening period II. Staphylococcus aureus could not be found on the chicken skin. An interesting finding was the increase of staphylococci while the intestinal enterococci were not detectable in the air of the barn toward the end of both fattening periods.